Elastic, electronic, and optical properties of hypothetical SnNNi3 and CuNNi3 in comparison with superconducting ZnNNi3

Abstract

A B S T R A C TThe elastic, electronic and optical properties of MNNi 3 (M= Zn, Sn and Cu) have been calculated using the plane-wave ultrasoft pseudopotential technique which is based on the first-principles density functional theory (DFT) with generalized gradient approximation (GGA). The optimized lattice parameters, independent elastic constants (C 11 , C 12 , and C 44 ), bulk modulus B, Compressibility K, shear modulus G, and Poisson's ratio υ, as well as the band structures, total and atom projected densities of states and finally the optical properties of MNNi 3 have been evaluated and discussed. The electronic band structures of the two hypothetical compounds show metallic behavior just like the superconducting ZnNNi 3 . Using band structures, the origin of features that appear in different optical properties of all the three compounds have been discussed. The large reflectivity of the predicted compounds in the low energy region might be good candidate materials as a coating to avoid solar heating.

Electronic, vibrational, superconducting and thermodynamic properties of cubic antiperovskite ZnNNi3

“…Unfortunately, there are no experimental data for the bulk modulus and its pressure derivative for us to compare. On the other hand, good agreement has been observed with previous theoretical values [21][22][23][24][25]27] for these quantities.…”

“…The equilibrium cubic lattice parameter and related structural properties were determined by calculating the total energy of the system at several values of lattice constant around the equilibrium one and fitting the total energy vs. a curve to the Murnaghan equation of state, as shown in Figure 1 Table 1, and compared with available experimental data [20] and results of other theoretical calculations [21][22][23][24][25]27]. Our calculated lattice constant value of 3.767 Å is only 0.3% larger than the experimental value [20] are found to be 1.90 Mbar and 4.83, respectively.…”

“…The energy band structure along the high-symmetry lines of the simple cubic Brillouin zone (BZ) is shown in Figure 2 3 .77 2.07 GGA [22] 3 .763 2.03 4.88 GGA [24] 3 .769 2.04 GGA [23] 3 .769 2.02 GGA [25] 3 .784 1.95 GGA [27] 3 .765 1.92 4.97 LDA [22] 3 .677 2.46 4.59 Experimental [20] 3 .756 energy bands along the -X and R-M symmetry directions. In particular, the value of this gap is 1.87 eV at the zone centre.…”

“…This material is the third Ni-rich antiperovskite series and the first antiperovskite nitride superconducting material. The structural and electronic properties of this material have been studied by using different theoretical approaches, such as the projector-augmented-wave method [21], the augmented plane waves plus local orbital method [22], the full-potential linearized augmented plane-wave method [23,24] and the plane-wave ultrasoft pseudopotential technique [25,26]. Results from these works have indicated that the density of states at the Fermi level is mainly dominated by Ni 3d orbitals.…”

Theoretical examination of superconductivity in the cubic antiperovskite Cr3GaN under pressure

“…The discovery of superconductivity in ZnNNi 3 has motivated several groups [24][25][26][27][28][29] to study the structural and electronic properties of this material. Very recently, attention has been directed to Cr-rich intermetallic antiperovskite materials because many of Cr compounds show superconductivity.…”